Paraffin scraper



Oct. 10, 1939. s. v. DODSON PARAFFIN SCRAPER Filed Nov. 16, 1938Patented Oct. 10, 1939 UNITED STATES 'PATE Nr OFFICE Claims.

This invention relates to a parafiln scraper. More particularly, theinvention relates to a device for cleaning well tubing and especiallythe removal of accumulated parafiin from the tubing of oil and gaswells.

The improved scraper forming the subject matter of this application isadapted to be suitably connected in the sucker rod at intervals and asthe conventional sucker rods are formed in sections, the improvedscrapers may to advantage, though not necessarily, be connected at thejoints between the sucker rod sections.

A primary object of this invention is the pro- Vision of a parafiinscraper which, when incorporated in the sucker rod of an oil well inmultiple will positively preclude the accumulation of paraflin on thewall of the tubing within which the sucker rod reciprocates.

A iurther object of the invention is the provision ofa paraflin scraperwhich is relatively simple in construction, durable and eflicient inoperation, and which is factored at relatively low cost.

For a more complete understanding of the nature and objects of ,theinvention, reference will be had to the following detailed description,taken in connection with the accompanying drawing, wherein Figure 1 is aside elevational view of the improved scraper, in accordance with apreferred embodiment thereof, a portion of the lower threaded end beingbroken away.

Figure 2 is a similar view as seen in a direction of right angles tothat of Figure 1.

Figure 3 is a top plan view of the scraper in the position illustratedin Figure 1.

Figure 4 is a transverse section in a plane represented by the line 4-4in Figure 1.

Figure 5 is a broken central vertical section of an oil well tubing,showing the improved scrapers operatively associated with the sucker rodin elevation.

Referring now in detail to the drawing, by reference characters, andwherein like characters designate like parts, S designates the improvedscraper, T the well tubing, and R the sucker rod which in practicereciprocates within the tubing.

The scraper S is a unitary structure and comprises the scraper sectionIII, an internally threaded end section II, and an externally threadedopposite end section l2, the latter end section being spaced from thescraper section In by the cylindrical sections l3 and II.

The scraper section In embodies asubstantially cylindrical core I! fromwhich project the capable of being manur tube engaging projections l6and I1 preferably integral with the core l5 as indicated in Figure 4.

I-he projections I6 are substantially half diamond-shaped in plan andthe projections I! are diamond-shaped in plan.

The projections I 6 are arranged in diametrically opposed pairs adjacentthe opposite ends of the core and with their opposed edges l8co-planular with the ends of the core l5.

The projections I! are diametrically opposed 10 with their minor axesparallel with the edges l8 and substantially midway the length of thecore l5. Thus there are four projections l6 and two projections I7 andthe outer surfaces of all of the projections are concentric with thecore l5 l5 and of a diameter substantially equal to the well tubing.

The projections I 6 have angularly disposed edges I9 and the projectionsI! have angularly disposed edges 20.

The edges l8 of projections l6 being at right angles to the axis ofreciprocation of the scraper in use act as scrapers and the angular ordiagonal edges l9 and 20 act as wedges to cut any accu- 'mulatedparaflin from the tubing wall, these latter edges also acting asscrapers.

As is clearly indicated in Figs. 3 and 4, the scraping edges l8 of theprojections l6 are of substantial arcuate extent, each extendingapproximately 45 degrees of the circumference of 0 the core 15. It is tobe also noted that the projections l! at their minor axes also eachextend approximately 45 degrees of the circumference of the core l5 andthat the apices of the projections 5 are in vertical alinement andapproximately midway of the lateral apices of the projections l1 andthat the vertically alined apices of the projections I! aresubstantially midway of the spaces between the projections I 6.

In other words, the projections l6 and I1 pro- 40 vide continuousscraping and wedging edges circumferentially of the core l5 and theprojections so disposed provide relatively wide intersecting passages 2|which freely permit parailin and well fluids to pass between theprojections from one end of the core to the other on either the up ordown stroke of the pump.

It will be further noted that the adjacent wedging edges l9 and 20 aresubstantially parallel thereby, providing passages 2| which are ofsubstantially uniform width whereby no ob- 'structions are oifered tothe free passage of paraflin and well fluids between the scraping andwedging projections.

The manner in which-the improved scrapers 2 are intended to be used isillustrated by way of example in Figure 5 wherein the scrapers S areinterposed in the sucker rod R at desired intervals, the scrapers beingconnected to the sucker rod sections by suitable connectors 23 and 24.

As will be seen upon inspection of Figure 5, the concentric outersurfaces of the projections I6 and I1 only engage the inner 'wall of thetubing T and as the sucker rod R is vertically reciprocated, thescraping and wedging edges l8, l9 and'2ll of the projections l6 and I1will prevent the accumulation of parafl'in on the tubing wall and byspacing the scrapers lengthwise of the sucker rod substantially equal tothe amplitude of reciprocation, the entire length of the tubing wallwill be kept clean.

During the reciprocation of the scrapers the passages M will permit thefree flow of paraffin and well fiuids past the projections l6 and I1.

Thus it will be seen that the improved scrapers in accordance with thisinvention effectively function to keep the tubing wall free fromparaffin accumulation and that the relative simplicity and ruggedness ofthe structures well adapts them to this particular use.

While I have disclosed but bodiment of the invention, sidered asillustrative only, the scope of the invention subjoined claims.

What I claim and desire to secure by United States Letters Patent is:

l. A scraper for a tubing of an oil well comprising an elongatedcylindrical member, a pair of diametrically opposed projections adjacenteach end of the cylindrical member and having horizontal co-planularscraping edges, each of the projections having wedging edges obliquelydisposed with respect to the axis of the cylindrical member, and a pairof diametrically opposed projections intermediate the first projectionsand each having a plurality of wedging edges substantially parallel withthe respective adjacent edges of the first projections.

2. A scraper for a tubing of an oil well comprising a cylindrical core,projections on the core adjacent each of the opposite ends thereof, eachof the projections presenting a horizontal scraping edge and a pair ofwedging edges converging to a point on the core inward of the respectiveend thereof.

3. The structure defined in claim 2 together with additional projectionson the core intermediate the first projections, the last namedprojections each presenting scraping and wedging edges, substantiallyparallel with the adjacent converging edges of the first namedprojections.

a single specific emsame is to be conand not restrictive, being definedin the 4. A scraper for a tubing of an oil well comprisinga cylindricalcore, a pair of diametrically opposed projections on the core adjacenteach end thereof, a pair of diametrically opposed projections on thecore intermediate the first projections, the projections havingsubstantially parallel opposed scraping and wedging edges definingintersecting passages of substantially uniform width extending from oneend of the core to the other.

5. The structure defined in claim 4 wherein the first named projectionshave horizontal scraping edges substantially co-planular with therespective ends of the core.

6. A scraper for a tubing of an oil well comprising a cylindrical core,a pair of projections on the core adjacent each end thereof and a pairof projections on the core intermediate the first projections, the firstprojections each having scraping and wedging edges converging toward thecentral transverse plane of the core, and the second projections havingscraping and wedging edges converging toward the opposite ends of thecore.

7 The structure defined in claim 6 wherein the first projections aresubstantially of triangular form in plan and in which each presents ahorizontal scraping edge, and wherein the second projections are diamondshaped in plan with their minor axes in said plane.

8. A scraper for a tubing of an oil well comprising a cylindrical core,a pair of diametrically opposed projections on the core adjacent eachend thereof, said projections each having a horizontal scraping edgeextending circumferentially of the core through an angle ofsubstantially 45 degrees and having a pair of wedging edges convergingtoward the central transverse plane of the core, a pair of diametricallyopposed projections on the core intermediate the ends thereof, each ofthe second named projections being diamond shaped in plan, the secondnamed projections having their major axes parallel with the axis of thecore and substantially midway of the adjacent ends of the horizontalscraping edges and with their minor axes in said plane.

9. The structure defined in claim 8 wherein said minor axes each extendthrough an angle of approximately 45 degrees.

10. A scraper for a tubing of an oil well comprising a cylindrical core,a pair of projections each of triangular form of the core adjacent eachend thereof, and a pair of projections each of diamond shape in plan onthe core intermediate the opposite ends thereof.

SIDNEY V. DODSON.

